It works just like quick connect fittings, when the collar is pushed forward, the bearings are free to move and release the blade.

Here's an example of an actual quick connect fitting being used as a release valve:

Another possibly way of putting it togther, in this case the air propells a piston as opposed to acting directly on the knife itself, with the added benefit of the gasses being retained thus greatly reducing firing noise.

jackssmirkingrevenge wrote:Another possibly way of putting it togther, in this case the air propells a piston as opposed to acting directly on the knife itself, with the added benefit of the gasses being retained thus greatly reducing firing noise.

I have the same arrester as that one and what I noticed was that it required a lot of force just to move the internal piston about an inch. I'm not sure if it could give the blade adequate acceleration. I'd also be concerned about the pushrod damaging the [plastic] internal piston due to the force. Only one way to find out...

PVC Arsenal 17 wrote:I wonder if you could adapt a water hammer arrester to drive a blade in the same manner.

Interesting thought, but you're still limited to what you can recock inline (unless you use a lever, vice or hydraulic press etc.) which is similar to the spring powered ballistic knives - as opposed to pneumatics where you add the pressure incrementally with a pump and can achieve a lot more compression.

I actually bought a couple of quick-connects with the intention of building the last design posted but now I'm not so sure that a how-to of a quiet ballistic knife that can be built by "anyone" is such a good idea.

i know this is an old thread but jack. eat your heart outbuiltthis some time ago and finally got to finish blade

Looks good seems a bit on the heavy side though. How easy is it to fire, I imagine there's a lot of friction on that single contact point.

... but in that case, what's the use of using standard parts when I have a lathe and mill?

I'm sure a lot of us here follow that rule given some of the crazy laws these days...

Certainly much of the stuff I've done recently I haven't published. I was talking to a technician doing some maintenance on one of our instruments and casually mentioned I had invested in some machine tools and his immediate reply was "What do you want them for? Weapons?" - I was a bit taken aback, "Well... uh, steam engines?". "Sure "

Looks good seems a bit on the heavy side though. How easy is it to fire, I imagine there's a lot of friction on that single contact point.[/quote]

its not to heavy bc the rear is aluminiom and the steel blade keeps it front heavy and going straight. also it has a lot of air volume. it used to be hard to shoot but i filed a 45 degree angle where the 90 degree angle was at the end of the notch to help with that